Printing devices for large format printing can be categorized according to the type of print media they are adapted to print onto and the manner in which the print media is moved during the printing process.
Roll-to-roll printers typically print onto roll-based print media and convey the print media from a first (feed) roller to second roller or basket. Flatbed printers, on the other hand, typically print onto rigid and flat print media with the print media being fixed to a table and the print head of the printer being moved across the print media during the printing process.
In general, a roll-to-roll printer may be preferred for printing onto flexible print media, such as paper, thin plastic film, clothing, etc., whereas a flatbed printer may be preferred for printing onto rigid print media, such as thick plastic, wood, glass, etc.
Advances in the field of large format printing have led to the development of hybrid printers which are able to print onto both roll-based print media and flat rigid print media. Such hybrid printers combine the functionality of a roll-to-roll printer and a flatbed printer in a single machine, thereby reducing cost and space requirements whilst maintaining the advantages associated with each printing type. This is important since large format printers may be over 5 m in width to cater for large format media and, accordingly, may also be very heavy and expensive.
An illustration of an exemplary hybrid printer device is shown in FIG. 1. The hybrid printer 1 comprises a table structure having a flat surface 4 upon which flat print media 6 can be positioned and secured. The printer also comprises a scan axis assembly 8 which is positioned above the flat surface 4 and adapted to guide the movement of a print head 2 coupled thereto. More specifically, the scan axis assembly 8 comprises an elongate member that extends in a lateral axis (as indicated generally by the arrow labeled “L”) above the flat surface 4 and is adapted to guide movement of the print head 2 in the lateral axis L. The scan axis assembly 8 is also adapted to be movable in a controlled manner along a longitudinal axis (as indicated generally by the arrow labeled “M”) of the flat surface 4.
The scan axis assembly 8 of the exemplary hybrid printer may be over 5.5 meters long and may weigh over 500 kg, for example.
By controlling the movement of the scan axis assembly 8 and the print head 2 along their respective axes whilst the print head 2 is also controlled to print, flat print media 6 secured on the flat surface 4 can be printed onto as required.
The hybrid printer 1 also comprises a feed roller 9 positioned at one end of the table structure and a rear roller (not visible) positioned adjacent to the feed roller 9. Roll-based flexible print media may then be fed from the feed roller 9 past the print head 2. Such roll-based flexible print media can then be printed onto by moving the print head 2 back and forth along the lateral axis L and controlling the print head 2 to print as the flexible print media is fed from the feed roller 9 to the rear roller past the print head 2.
Thus, it will be understood that the hybrid printer 1 of FIG. 1 combines the functionality of a roll-to-roll printer and a flatbed printer in a single printing machine.
Despite the advantages associated with hybrid printers, they also exhibit some drawbacks. One such drawback is that existing hybrid printers are generally unable to cater for print media of differing thicknesses due to their size and weight and the positioning accuracy required. In other words, they do not allow the optimization of Print-head to Print-media Spacing (PPS).
Thus, there is a need to design a hybrid printer that can cater for print media of differing thicknesses, and therefore enable a PPS to be adjusted as necessary. It is also desirable that such a printer is able to print with high accuracy, independently of the thickness of the print media.